The European Union has come up with a plan to help reduce the number of migrants - pressing African leaders into taking back thousands of people refused asylum.

As an international migration summit began in Malta, the EU announced a plan to expel some refugees who do not qualify for asylum and give them papers to fly to Africa, calling on African countries to let the migrants travel onwards to their home.

A top African Union official called the idea "unheard of" and migration experts said it represents a sign of desperation.

The special "laissez passer" travel documents for Africans without ID are aimed at easing their return back to countries they left or travelled through.

In essence, it means the EU would decide where a person without a passport has come from in Africa - tantamount to the EU designating the nationality of someone on behalf of his home country.

Iverna McGowan, acting director of Amnesty International's EU office, said: "It is another form of taking short cuts on procedures. People returned to countries of transit risk being faced with arbitrary detention and having their rights to asylum and to work violated."

The measure is one of a number that the Europeans want their African counterparts to accept - particularly the nations around lawless Libya, from where most people set off on perilous sea voyages to Europe - to speed up the return home of migrants.

The talks on the Mediterranean island are being held not far from where rescue ships have plucked thousands of people from the seas this year.

According to the International Organisation for Migration, almost 800,000 people have entered Europe by sea this year. The EU predicts that three million more could arrive by 2017.

Many people arrive in Europe without identity papers. Some claim to be Syrians or Iraqis, to increase their chances of being granted asylum.

The two-day summit in Valletta will also discuss longer-term measures to fight poverty, climate change and conflict, the main causes of people leaving Africa in the first place.